Saturday, March 5, 2011

I've written about the dog-toxicity of the popular sugar substitute xylitol so often and so fervently that a Google search for "xylitol and dogs" digs up my past posts on the subject among the first several findings. And that's cool. But it's not nearly enough. Indeed, the fact that I'm up there tells me precious few people are getting the news. Which is why I keep trying …

Yes, xylitol is still killing dogs … more dogs than ever before. This, despite my efforts and those of like-minded big mouths who seek to inform all U.S. consumers that xylitol is a menace to dogdom.

How menacing? A few sugar-free breath fresheners, a pack of gum, a spilled tin of mints, a sugar-free dessert cup. It takes only a little of this toxin to send a dog into hypoglycemia-induced seizures, and just a little bit more to bring on liver failure.

And what's worse is not so much its extreme toxicity … but its insidiousness.

Let me explain:

Xylitol is a great product. It's a natural extract from the birch tree, and it takes only a little bit of this stuff to sweeten a whole lot. It's therefore less expensive than other sugar substitutes. And it happens to taste better than most of them. Diabetics everywhere can rejoice! The tooth fairy, too.

All of which is why consumer product manufacturers have been slowly and quietly replacing other sweeteners with xylitol … in everything, not just products that are labeled sugar-free.

And that's the trouble. When I first started writing about xylitol three or four years ago the number of consumer products containing xylitol numbered less than a hundred in the U.S. Moreover, they were largely restricted to the arena of sugar-free gums and foods. Fast-forward to today and the list is way longer and much more diverse. You can find xylitol in everything from Flintstones vitamins to commonly prescribed drugs.

These latter products pose more of a problem for dog owners and veterinarians for a variety of reasons.

These products never used to contain xylitol. In fact, I used to recommend Flintstones vitamins for my patients. Now I have to caution my clients to stick to pet-only brands and to be very diligent about reading labels. But it took months before I became aware of the change in this brand's ingredients. (So you know, xylitol is included in only a few of the Flintstones formulations, not all.)

What's worse — and even more stressful for veterinarians — is that it's not just common consumer products anymore that we have to watch for. The human versions of drugs, especially the children's elixirs, are now being formulated with xylitol for greater pediatric palatability. Unfortunately, the lower doses in the kids' meds are exactly what some of our smaller animal patients require.

Got a little dog who needs hycodan syrup for a cough, or the bronchodilator theophylline for breathing? Even if you've been getting a drug for months or years as an elixir from the same exact pharmacy, beware. Preparations of these drugs may soon change to reflect the widening market for xylitol as a sweetener.

Case in point: This week I sought to relieve a clients' small dog of back pain associated with recurrent episodes of intervertebral disc disease. In so doing, I prescribed a dog-only non-steroidal anti-inflammatory drug, and the smallest dosage of gabapentin (used for both seizures and neurogenic pain) currently formulated. But the pharmacy had run out of the 100 mg capsules, which is why I received a call from the pharmacist to see if I would OK the liquid (elixir) version instead.

Now, I'd like to say I'm always up on every single drug and all the new formulations, but I'm not. It's just too damn much info to consume on a regular basis. I had, however, just read through Plumb's Veterinary Drug Handbook on this exact point: available formulations of gabapentin. And guess what? Some commercially prepared versions of liquid gabapentin have xylitol in them — and it was one of these very versions my pharmacist was offering.

The same drug I was offering my patient might have killed her had I not known about the change!

Now, I don't know how much of the elixir it would've taken to send her into seizures, but rest assured, this little dog was already getting the high end of the drug's dose, so I think I'm justified in fearing the worst for other dogs all over the country whose pharmacists don't make the call (it happens all the time), or whose veterinarians haven't yet heard of the dangers pediatric elixirs now pose to animals.